<style>
    body {
        padding: 20px;
    }
    * {
        margin: 0;
        padding: 0;
        font-family: Arial;
    }
    ol {
        font-size: 13px;
        padding-left: 15px;
    }
    h3 {
        padding-bottom: 10px;
    }
    a {
        color: #005c90;
        text-decoration: none;
    }
    a:hover {
        text-decoration: underline;
    }
</style>

<?php
$dir    = '.';
$files1 = scandir($dir);
$files = array();

foreach($files1 as $filename){
    if(pathinfo($filename, PATHINFO_EXTENSION) == 'html'){
        $files[] = $filename;
    }
}

?>
<h3>HTML Preview:</h3>
<ol>
<?php foreach($files as $file): ?>
    <li>
        <a href="<?= $file; ?>"><?= $file; ?></a>
    </li>
<?php endforeach; ?>
</ol>